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>Chapter 23. Routine Database Maintenance Tasks</H1
><DIV
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><DL
><DT
><B
>Table of Contents</B
></DT
><DT
>23.1. <A
HREF="routine-vacuuming.html"
>Routine Vacuuming</A
></DT
><DD
><DL
><DT
>23.1.1. <A
HREF="routine-vacuuming.html#VACUUM-BASICS"
>Vacuuming Basics</A
></DT
><DT
>23.1.2. <A
HREF="routine-vacuuming.html#VACUUM-FOR-SPACE-RECOVERY"
>Recovering Disk Space</A
></DT
><DT
>23.1.3. <A
HREF="routine-vacuuming.html#VACUUM-FOR-STATISTICS"
>Updating Planner Statistics</A
></DT
><DT
>23.1.4. <A
HREF="routine-vacuuming.html#VACUUM-FOR-WRAPAROUND"
>Preventing Transaction ID Wraparound Failures</A
></DT
><DT
>23.1.5. <A
HREF="routine-vacuuming.html#AUTOVACUUM"
>The Autovacuum Daemon</A
></DT
></DL
></DD
><DT
>23.2. <A
HREF="routine-reindex.html"
>Routine Reindexing</A
></DT
><DT
>23.3. <A
HREF="logfile-maintenance.html"
>Log File Maintenance</A
></DT
></DL
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><P
>   <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
>, like any database software, requires that certain tasks
   be performed regularly to achieve optimum performance. The tasks
   discussed here are <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>required</I
></SPAN
>, but they
   are repetitive in nature and can easily be automated using standard
   tools such as <SPAN
CLASS="APPLICATION"
>cron</SPAN
> scripts or
   Windows' <SPAN
CLASS="APPLICATION"
>Task Scheduler</SPAN
>.  It is the database
   administrator's responsibility to set up appropriate scripts, and to
   check that they execute successfully.
  </P
><P
>   One obvious maintenance task is the creation of backup copies of the data on a
   regular schedule.  Without a recent backup, you have no chance of recovery
   after a catastrophe (disk failure, fire, mistakenly dropping a critical
   table, etc.).  The backup and recovery mechanisms available in
   <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> are discussed at length in
   <A
HREF="backup.html"
>Chapter 24</A
>.
  </P
><P
>   The other main category of maintenance task is periodic <SPAN
CLASS="QUOTE"
>"vacuuming"</SPAN
>
   of the database.  This activity is discussed in
   <A
HREF="routine-vacuuming.html"
>Section 23.1</A
>.  Closely related to this is updating
   the statistics that will be used by the query planner, as discussed in
   <A
HREF="routine-vacuuming.html#VACUUM-FOR-STATISTICS"
>Section 23.1.3</A
>.
  </P
><P
>   Another task that might need periodic attention is log file management.
   This is discussed in <A
HREF="logfile-maintenance.html"
>Section 23.3</A
>.
  </P
><P
>   <A
HREF="http://bucardo.org/wiki/Check_postgres"
TARGET="_top"
><SPAN
CLASS="APPLICATION"
>check_postgres</SPAN
></A
>
   is available for monitoring database health and reporting unusual
   conditions.  <SPAN
CLASS="APPLICATION"
>check_postgres</SPAN
> integrates with
   Nagios and MRTG, but can be run standalone too.
  </P
><P
>   <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> is low-maintenance compared
   to some other database management systems.  Nonetheless,
   appropriate attention to these tasks will go far towards ensuring a
   pleasant and productive experience with the system.
  </P
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